This application relates to the art of employing radio frequency data communication networks to effect point of sale ("POS") transactions. The invention is particularly applicable to credit card transactions common to retail sales operations, although it will be appreciated that the invention has broader applicability to any transaction that requires the transmission and verification of coded data.
Various types of communication networks have evolved in response to increasing needs for information exchange. Among the more familiar types of communication networks are cellular telephone technology and modem technology. The former is primarily oriented to voice communication, and the latter to more general data transmission such as between computers or fax machines. Both technologies employ the existing infrastructure of fixed telephone lines, and the fees associated with the use of these networks are accrued according to the amount of time that a user is connected to a telephone line.
Recently another type of data communication network has emerged, which enables information exchange by the sending and receiving of data through high frequency radio signals. The radio frequency data communication networks require a new infrastructure of receiving and transmitting stations connected to regional and national control centers. This control hierarchy provides the wide geographical coverage that enables the reception and re-transmission of signals beyond the range of the individual user/transmitters.
Such network infrastructures are provided, in the United States, by the Mobitex network, owned and operated by RAM Mobile Data and by Ardis, a joint venture of Motorola and IBM. Both networks employ packet switched data transmission, which aggregates digital data into packets that are then transmitted in radio frequency bursts. The fees for usage of the data communication network are then charged according to the number of data packets transmitted by the users.
The technology for POS credit transactions is also well known. A prospective credit purchaser moves a credit card through a card reader slot or manually enters a number, thereby supplying information concerning the account number of the card holder. This account number, along with the amount of the contemplated purchase, is transmitted to a central authorization center. The approval or disapproval of the transaction by a "host device" at the authorization center is then transmitted back from the authorization center to the POS.
Existing POS equipment receives and transmits data over telephone lines, using modem technology. Modems use a streaming or bit by bit serial data transmission. Moreover, in stores with many checkout counters or registers, the POS devices are "daisy-chained" or series connected to a limited number of telephone lines. During high volume periods a queuing problem develops that creates undesirable delays in obtaining individual authorizations.
POS devices equipped to utilize a radio frequency data communication network would increase the speed of data transmission and eliminate or substantially reduce high volume queuing problems. The radio frequency data communication network, transmitting at approximately 8,000 bits/sec., can quite quickly accommodate a data packet and clear the channel for other traffic. Also, at this stage of its development, the network has excess transmission capacity that further contributes to faster transmission.
Existing POS devices, however, are designed to communicate with modems, using serial data transmission algorithms such as the Mastercard Automated Point-Of-Sale Program ("MAPP"). Devices equipped to transmit data packets over a radio frequency data communication network are designed to communicate using other algorithms, such as the Mobitex Asychronous Communication ("MASC") algorithm.
Moreover, a wholesale conversion to new POS devices dedicated to operating with the radio frequency data communication networks is not practical at this time. Some credit card companies, which have not yet affiliated with radio frequency data communication networks, may not be connected to the networks at the authorization centers. Many retailers may also wish to retain the option of employing existing modem lines rather than switching entirely to radio frequency data transmission.
Thus, there is a need to transmit and receive POS transaction data over radio frequency data communication networks in conjunction with existing POS card readers. There is also a concomitant need to maintain an option to utilize an existing modem link, either upon recognition of a particular type of credit card, or at the external command of a POS user.